Fix key base equality and spaceship operators

[magneland]

I ran into this issue when trying to use Rails.cache.fetch.

Specifically there is a fallback condition that tried to compare:

@value == true (where @value was a JWK)

and this gem raised an error:

undefined method `[]' for true:TrueClass

I haven't run into the spaceship operator issue, but I figured it is similar enough to fix at the same time.

[magneland]

FYI I followed some of the recommendations here: https://shopify.engineering/implementing-equality-in-ruby

[anakinj]

Thank you for taking time fixing this.

Would you have the time to add a changelog entry for this into the changelog file. I had forgotten to update it after the last release, fixed now on main so if you rebase your branch you should have a place to add an entry.